website: stop emitting the stray /2026 dated post

src/_posts/index.md exists only to drive hexo-generator-index (the
homepage), but Hexo also rendered it as a dated post at /2026/06/21/index/
— unlinked, empty, indexable junk. Pin that post to a fixed permalink and
strip it after generate in the Makefile, keeping the homepage intact.

Author: changkun

website/Makefile

@@ -12,6 +12,7 @@ all: clean
 	cp -r ../code ./src/modern-cpp/
 	npx hexo generate
 	mv public/index.html public/modern-cpp/index.html
+	rm -rf public/_generated_home_stub
 s: all
 	node_modules/serve/bin/serve.js ./public
 clean:

website/src/_posts/index.md

@@ -1,4 +1,10 @@
 ---
 index: true
 type: book-zh-cn
+# This file only exists to drive hexo-generator-index (the homepage). Hexo also
+# renders it as a standalone post; pin that copy to a fixed path so the build
+# can strip it deterministically (see website/Makefile) instead of leaving a
+# stray dated permalink like /2026/06/21/index/.
+permalink: _generated_home_stub/index.html
+date: 2016-01-01 00:00:00
 ---